Design Of Multicopter Power System And Vibration Isolation System For Long Endurance And Heavy Lift

Power system(power unit) has a significant effect on the performance of UAV. It is difficult for the existing UAV power system to reconcile the power performance and control performance. To maximize the serviceability of UAV, this thesis designed a novel multicopter power system and vibration isolation system for long endurance and heavy lift simultaneously, starting with the analysis of different power sources, actuators and power layout forms. The following aspects were involved in this thesis:(1) According to the comprehensive comparison of multiple factors, this thesis proposed a UAV general design which chose a two-stroke gasoline engine as the power source, a twoblade fixed pitch propeller as the actuator and a multicopter structural pattern as the power layout form.(2) This thesis designed a test bench for the power performance of the multicopter to quantitatively compare the difference between the propulsive efficiencies of coaxial rotor pattern and electricity generation pattern. Experimental results show that the latter is better.(3) Based on analysis of vibration source, this thesis designed a test bench for the power system vibration using a six-dimension force sensor to test the opposed-twin-cylinder engine and the propeller. This thesis processed all the data by spectral analysis, which provides the theoretic basis for the vibration isolation system design.(4) The degeneration condition was discussed by quantitatively analyzing two-degree-offreedom vibration model of the multicopter. With the use of negative vibration isolation technology, this thesis designed a two-layer vibration isolation system of the engine and a lever amplifier vibration isolation system of the propeller, whose rationalities were verified by quantitative calculation.